I really enjoy using both systems, although, understandably I compose differently with both setups.
I didn't use my Rollei in Iceland, but after Iceland I travelled on to places like New York and Havana where my Rollei was used everyday. It's a real joy composing with the Rollei.
I should point out that landscape photography is not something I am used to, I live in Hertfordshire, just outside London and safe for a few flat fields it's not exactly a training ground for the next Ansel Adams. 😉
I'm not sure about the differing saturation levels when comparing the cameras, they appear the same to me. It's more likely a post processing difference, I became a Mac-Convert not long after buying my Pentax.